floppy: Do not probe number of cylinders in drive signal test

The probe test:
1. It isn't a signal test
2. It bangs the head on a 48-tpi drive
3. It doesn't actually find the true cylinder range as it
   never steps beyond cylinder 79

Thus the probe is fairly pointless and best to simply remove it.

testkit/floppy.c

@@ -310,13 +310,8 @@ static unsigned int drive_signal_test(unsigned int drv, struct char_row *r)
         drive_wait_ready();
 
         seek_cyl0();
-        if (cur_cyl == 0) {
-            unsigned int nr_cyls;
-            seek_track(159);
-            nr_cyls = seek_cyl0() + 1;
-            if (cur_cyl == 0)
-                sprintf(s, "-- DF%u: %u cylinders --", drv, nr_cyls);
-        }
+        if (cur_cyl == 0)
+            sprintf(s, "-- DF%u: %u cylinders --", drv, drive_param.nr_cyls);
         if (cur_cyl < 0)
             sprintf(s, "-- DF%u: No Track 0 (Drive not present?) --", drv);
         print_line(r);